G

Figure 2. The notes of G in different octaves on the stave,
in scientific pitch notation, and on a standard piano keyboard,
with frequencies shown in hertz.

G is one of the notes in the diatonic scale; it is the fifth tone (dominant)
of the C major scale. In solfege, it is called Sol.

Using a reference frequency of 440 Hz for the A above middle C, and calculated in equal temperament, middle G (G4) has
a frequency of 391.995 Hz. The 3rd string of a guitar in open tuning
is tuned to G3.